U.S. patent application number 11/531960 was filed with the patent office on 2007-06-14 for light fixture.
Invention is credited to Brian G. Brown, Stephen H. Lydecker, John T. III Mayfield.
Application Number | 20070133215 11/531960 |
Document ID | / |
Family ID | 46123974 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070133215 |
Kind Code |
A1 |
Mayfield; John T. III ; et
al. |
June 14, 2007 |
Light Fixture
Abstract
A light fixture or troffer for directing light emitted from a
light source toward an area to be illuminated, including a
reflector assembly within which the light source is positioned and
a lens assembly detachably secured to a portion of the reflector
assembly such that a lens of the lens assembly overlies the light
source and such that substantially all of the light emitted from
the light source passes through the lens assembly. The reflector
assembly including at least one longitudinally extending hollow
that extends inwardly to a central portion between respective first
and second hollow edges. Each hollow has a plurality of
longitudinally extending male ridges.
Inventors: |
Mayfield; John T. III;
(Loganville, GA) ; Lydecker; Stephen H.;
(Snellville, GA) ; Brown; Brian G.; (Decatur,
GA) |
Correspondence
Address: |
NEEDLE & ROSENBERG, P.C.
SUITE 1000
999 PEACHTREE STREET
ATLANTA
GA
30309-3915
US
|
Family ID: |
46123974 |
Appl. No.: |
11/531960 |
Filed: |
September 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10970615 |
Oct 21, 2004 |
|
|
|
11531960 |
Sep 14, 2006 |
|
|
|
60580996 |
Jun 18, 2004 |
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Current U.S.
Class: |
362/382 |
Current CPC
Class: |
F21S 8/04 20130101; F21V
13/04 20130101; F21Y 2113/00 20130101; F21V 23/026 20130101; F21V
5/02 20130101; F21V 17/164 20130101; F21V 23/02 20130101; F21Y
2103/00 20130101 |
Class at
Publication: |
362/382 |
International
Class: |
F21V 19/00 20060101
F21V019/00 |
Claims
1. A light fixture, comprising: a reflector assembly comprising: an
elongated base member having a first longitudinally extending side
edge and an opposed second longitudinally extending side edge; and
at least one longitudinally extending hollow having a
longitudinally extending first hollow edge and a longitudinally
extending second hollow edge, at least a portion of a cross-section
of the hollow normal to the longitudinal axis of the hollow having
a generally curved shape, the at least one hollow extending
inwardly toward a central portion defined by and between the
respective first and second hollow edges, said at least one hollow
comprising a plurality of longitudinally extending male ridges,
wherein each ridge comprises a first surface and an adjoining
second surface, wherein each first surface is positioned at a first
angle relative to a reflector plane that bisects the longitudinal
axis of the at least one hollow normal to a base member plane that
bisects the respective side edges of the base member, wherein the
first angle is an acute angle such that the first surface of each
ridge faces substantially inwardly toward the reflector plane, and
wherein the second surface of each ridge is positioned at a second
angle relative to the reflector plane.
2. The light fixture of claim 1, wherein the second angle of the
second surface is greater than the first angle of an adjoining
first surface, and wherein the second surface of each respective
ridge is positioned closer to the reflector plane than the first
surface of each such ridge.
3. The light fixture of claim 2, further comprising a linear light
source having at least one end, the linear light source being
mounted within a portion of the central portion of the reflector
assembly.
4. The reflector assembly of claim 2, wherein the second angle of
the second surfaces of a first portion of the plurality of male
ridges is an acute angle such that the respective second surfaces
of said first portion of the plurality of male ridges face
substantially inwardly toward the reflector plane.
5. The reflector assembly of claim 4, wherein the second angle of
the second surface of a second portion of the plurality of male
ridges is an obtuse angle such that the respective second surfaces
of said second portion of the plurality of male ridges face
substantially outwardly relative to the reflector plane.
6. The light fixture of claim 5, wherein the second surface of each
respective ridge has a cross-sectional length that is less than the
cross-sectional length of its first surface.
7. The light fixture of claim 6, wherein the cross-sectional length
of the second surface of each respective ridge is between about 30
and 50 percent of the cross-sectional length of its first
surface.
8. The light fixture of claim 1, wherein the plurality of ridges
comprises a series of longitudinally extending male ridges defined
within each side of the at least one hollow divided by the central
portion of said hollow.
9. The light fixture of claim 8, wherein each series of ridges
extends outwardly, in opposed directions from the longitudinal axis
of the reflector assembly toward a respective one of the first and
second hollow edges.
10. The light fixture of claim 9, wherein each series of ridges is
a substantial mirror image of the other.
11. The light fixture of claim 9, wherein the at least one hollow
comprises a pair of longitudinally extending hollows, and wherein
each such hollow is positioned such that the respective reflector
planes of each hollow extend substantially parallel to one
another.
12. The light fixture of claim 1, wherein the reflector assembly
comprises at least one end face forming an obtuse angle with
respect to the longitudinal axis of the reflector assembly.
13. The light fixture of claim 12, wherein the at least one end
face defines an opening that is configured for receiving at least a
portion of the light source therein.
14. The light fixture of claim 1, wherein the base member further
has base surface, a first end edge and a spaced second end edge
that are connected to the respective first longitudinally extending
side edge and the second longitudinally extending side edge one
another along their common side edges, and a base longitudinal axis
extending between the first end edge and the second end edge of the
base member, wherein a portion of said base surface defines the at
least one hollow.
15. The light fixture of claim 1, wherein the portions of the
hollow extending between its central portion and its respective
first and second hollow edges form a generally curved reflective
surface.
16. The light fixture of claim 1, wherein the central portion of
the hollow defines a longitudinally extending trough that extends
inwardly away from the surface of the hollow.
17. The light fixture of claim 16, further comprising: a lens
assembly comprising an elongated lens that has a lens longitudinal
axis that is generally parallel to the light source longitudinal
axis and a central lens portion that is curved in a plane that is
transverse with respect to the lens longitudinal axis, the lens
being configured for detachable connection to a portion of said
trough, the central lens portion having a prismatic surface that
defines a face oriented toward and spaced from the light source,
wherein the lens is positioned with respect to said trough such
that substantially all of the light emitted by the light source
passes through the lens, and wherein the reflector assembly is
configured to block high angle glare in the transverse direction
with respect to the light source longitudinal axis and to optically
control high angle glare in the longitudinal direction of the light
source longitudinal axis.
18. A reflector assembly for a light fixture that is mountable in
relation to a ceiling plane, comprising: at least one
longitudinally extending hollow having a longitudinally extending
first hollow edge and a longitudinally extending spaced second
hollow edge, at least a portion of a cross-section of the hollow
normal to a longitudinal axis of the hollow having an at least
partially arcuate shape, the at least one hollow extending inwardly
toward a central portion thereof defined by and between the
respective first and second hollow edges, said at lest one hollow
including a plurality of longitudinally extending ridges, each such
ridge comprising a first surface and an adjoining second surface
with the first surface positioned at a first angle relative to a
reflector plane that bisects the longitudinal axis of the hollow
normal to the ceiling plane, the first angle being an acute angle,
such that each first surface faces substantially inwardly toward
the reflector plane, wherein each second surface is positioned at a
second angle relative to the reflector plane that is greater than
the first angle of an adjoining first surface, and wherein the
second surface of each respective male ridge is positioned closer
than the first surface with respect to the reflector plane.
19. The reflector assembly of claim 18, wherein the second angle of
the second surfaces of a first portion of the plurality of male
ridges is an acute angle such that the respective second surfaces
of said first portion of the plurality of male ridges face
substantially inwardly toward the reflector plane.
20. The reflector assembly of claim 19, wherein the second angle of
the second surface of a second portion of the plurality of male
ridges is an obtuse angle such that the respective second surfaces
of said second portion of the plurality of male ridges face
substantially outwardly relative to the reflector plane.
21. The reflector assembly of claim 18, wherein the second surface
of each male ridge has a cross-sectional length that is less than
the cross-sectional length of the first surface.
22. The reflector assembly of claim 21, wherein the cross-sectional
length of the second surface is between about 30 and 50 percent of
the cross-sectional length of the first surface.
23. The reflector assembly of claim 18, wherein the plurality of
ridges comprises a pair of opposed sets of male ridges.
24. The reflector assembly of claim 23, wherein each pair of ridges
comprises a first set of male ridges and an opposed second set of
male ridges, wherein the respective first and second sets of ridges
extend outwardly and in opposed directions away from the
longitudinal axis of the reflector assembly toward the respective
first and second hollow edges of the at least one hollow.
25. The reflector assembly of claim 24, wherein the first set of
ridges is a substantial mirror image of the second set of male
ridges.
26. The reflector assembly of claim 24, wherein the at least one
hollow comprises a pair of longitudinally extending hollows
positioned such that the respective reflector planes of each such
hollow extend substantially parallel to one another.
27. The reflector assembly of claim 21, wherein the reflector
assembly comprises at least one end face forming an obtuse angle
with respect to the longitudinal axis of the reflector
assembly.
28. The reflector assembly of claim 21, wherein the portions of the
hollow extending between its central portion and its respective
first and second hollow edges form a generally curved reflective
surface.
29. The reflector assembly of claim 21, wherein the central portion
of the at least one hollow is symmetrically formed with respect to
the first hollow edge and the second hollow edge, and wherein the
central portion of the at least one hollow defines a longitudinally
extending trough that extends inwardly away from the surface of the
hollow.
30. A reflector assembly for a light fixture that is mountable in
relation to a ceiling plane, comprising: at least one
longitudinally extending hollow having a longitudinally extending
first hollow edge and a longitudinally extending spaced second
hollow edge, at least a portion of a cross-section of the hollow
normal to said longitudinal axis having a generally curved shape,
said hollow comprising a plurality of longitudinally extending
ridges comprising a first surface and an adjoining second surface,
wherein each ridge has an asymmetric shape in which the second
surface thereof has a cross-sectional length which is less than the
cross-sectional length of the first surface, wherein each first
surface is positioned at a first angle relative to a reflector
plane that bisects the longitudinal axis of the hollow normal to
the ceiling plane, and wherein the second surface of each
respective ridge is positioned closer to the reflector plane than
is its the first surface.
31. The reflector assembly of claim 30, wherein the first angle is
an acute angle and each first surface faces substantially inwardly
toward the reflector plane.
32. The reflector assembly of claim 31, wherein each second surface
is positioned at a second angle relative to the reflector plane
that is greater than the first angle of an adjoining first surface
relative to the reflector plane.
33. The reflector assembly of claim 32, wherein the second angle of
the second surfaces of a first portion of the plurality of male
ridges is an acute angle such that the respective second surfaces
of said first portion of the plurality of male ridges face
substantially inwardly toward the reflector plane.
34. The reflector assembly of claim 33, wherein the second angle of
the second surface of a second portion of the plurality of male
ridges is an obtuse angle such that the respective second surfaces
of said second portion of the plurality of male ridges face
substantially outwardly relative to the reflector plane.
35. The reflector assembly of claim 30, wherein the cross-sectional
length of the second surface is between about 30 and 50 percent of
the cross-sectional length of the first surface.
36. The reflector assembly of claim 30, wherein the plurality of
male ridges comprises a pair of opposed sets of male ridges.
37. The reflector assembly of claim 36, wherein the pair of opposed
sets of male ridges comprises a first set of male ridges and an
opposed second set of male ridges, wherein the respective first and
second sets of male ridges extend outwardly, in opposed directions,
radially about the longitudinal axis of the reflector assembly and
toward a respective one of the respective first and second hollow
edges.
38. The reflector assembly of claim 35, wherein the first set of
ridges is a substantially mirrored image of the second set of
ridges.
39. The reflector assembly of claim 30, wherein the at least one
longitudinally extending hollow comprises a pair of longitudinally
extending hollows positioned such that the reflector plane of each
of said hollows extends substantially parallel to one another.
40. The reflector assembly of claim 30, wherein the reflector
assembly comprises at least one end face forming an obtuse angle
with respect to the longitudinal axis of the reflector
assembly.
41. The reflector assembly of claim 30, wherein the at least one
hollow extends inwardly toward a central portion defined by and
between the respective first and second hollow edges, and wherein
the portions of the hollow extending between the central portion
and the respective first and second hollow edges form a generally
curved reflective surface.
42. The reflector assembly of claim 30, wherein the central portion
is positioned symmetrically with respect to the first and second
hollow edges and defines a longitudinally extending trough
extending away from the surface of the hollow.
43. A light fixture, comprising: a reflector assembly comprising at
least one longitudinally extending hollow, said longitudinally
extending hollow comprising a plurality of longitudinally extending
male ridges, wherein each ridge has a first surface and an
adjoining second surface; a light source configured for mounting
within a portion of the longitudinally extending hollow; and means
for controlling the light generated from the light source that is
incident on the respective first and the second surfaces of the
plurality of longitudinally extending male ridges to form at least
one longitudinally extending shadow in the reflector assembly,
wherein each longitudinally extending shadow has the appearance of
a dark stripe to an external viewer.
44. A reflector assembly positioned with respect to a light source
that is adapted to produce light, comprising: a plurality of male
ridges, wherein each ridge has a first surface and an adjoining
second surface; and means for controlling the light incident on
portions of the respective first and the second surfaces of the
plurality of male ridges such that portions of the male ridges are
illuminated and portions of the male ridges are non-illuminated,
wherein the respective illuminated and non-illuminated portions of
the male ridges are positioned in alternating and adjoining
relationship to each other, and wherein, to an external viewer, the
non-illuminated portions of the male ridges have the appearance of
dark shapes relative to the illuminated portions of the male
ridges.
Description
[0001] This application is a continuation-in-part application of
U.S. Utility patent application Ser. No. 10/970,615, entitled
"Light Fixture and Lens Assembly for Same," filed on Oct. 21, 2004,
and claims priority to and the benefit of U.S. Provisional
Application No. 60/580,996, entitled "Light Fixture and Lens
Assembly for Same," filed on Jun. 18, 2004, all of which are
incorporated in their entirety in this document by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to light fixtures
for illuminating architectural spaces. The invention has particular
application in light fixtures using fluorescent lamps as the light
source.
[0004] 2. Background Art
[0005] Numerous light fixtures for architectural lighting
applications are known. In the case of fixtures that provide direct
lighting, the source of illumination may be visible in its entirety
through an output aperture of the light fixture or shielded by
elements such as parabolic baffles or lenses. A light fixture
presently used in a typical office environment comprises a troffer
with at least one fluorescent lamp and a lens having prismatic
elements for distributing the light. Also known are light fixtures
that use parabolic reflectors to provide a desired light
distribution. The choice of light fixture will depend on the
objectives of the lighting designer for a particular application
and the economic resources available. To meet his or her design
objectives, the lighting designer, when choosing a light fixture,
will normally consider a variety of factors including aesthetic
appearance, desired light distribution characteristics, efficiency,
lumen package, maintenance and sources of brightness that can
detract from visual comfort and productivity.
[0006] An important factor in the design of light fixtures for a
particular application is the light source. The fluorescent lamp
has long been the light source of choice among lighting designers
in many commercial applications, particularly for indoor office
lighting. For many years the most common fluorescent lamps for use
in indoor lighting have been the linear T8 (1 inch diameter) and
the T12 ( 11/2 inch diameter). More recently, however, smaller
diameter fluorescent lamps have become available, which provide a
high lumen output from a comparatively small lamp envelope. An
example is the linear T5 (5/8 inch diameter) lamp manufactured by
Osram/Sylvania and others. The T5 has a number of advantages over
the T8 and T12, including the design of light fixtures that provide
a high lumen output with fewer lamps, which reduces lamp disposal
requirements and has the potential for reducing overall costs. The
smaller-diameter T5 lamps also permit the design of smaller light
fixtures.
[0007] Some conventional fluorescent lamps, however, have the
significant drawback in that the lamp surface is bright when
compared to a lamp of larger diameter. For example, a conventional
T5 lamp can have a surface brightness in the range of 5,000 to
8,000 footlamberts (FL), whereas the surface brightness of the
larger T8 and T12 lamps generally is about 3,000 FL and 2,000 FL,
respectively (although there are some versions of linear T8 and T12
lamps with higher brightness). The consequence of such bright
surfaces is quite severe in applications where the lamps may be
viewed directly. Without adequate shielding, fixtures employing
such lamps are very uncomfortable and produce direct and reflected
glare that impairs the comfort of the lighting environment.
Heretofore, opaque shielding has been devised to cover or
substantially surround a fluorescent lamp to mitigate problems
associated with light sources of high surface brightness; however,
such shielding defeats the advantages of a fluorescent lamp in
regions of distribution where the lamp's surfaces are not directly
viewed or do not set up reflected glare patterns. Thus, with
conventional shielding designs, the distribution efficiencies and
high lumen output advantages of the fluorescent lamp can be
substantially lost.
[0008] A further disadvantage to traditional parabolic and
prismatic troffers is the presence of distracting dynamic changes
in brightness level and pattern as seen by a moving observer in the
architectural space. Additionally, traditional parabolic and
prismatic troffers allow direct or only slightly obscured views of
the lamp source(s)) at certain viewing angles (low angles for both
the parabolic and prismatic and most transverse angle for
prismatic). This unaesthetic condition is remedied by indirect and
direct-indirect fixture designs, but typically with a significant
loss of efficiency.
[0009] Another known solution to the problem of direct glare
associated with the use of high brightness fluorescent lamps is the
use of biax lamps in direct-indirect light fixtures. This approach
uses high brightness lamps only for the uplight component of the
light fixture while using T-8 lamps with less bright surfaces for
the light fixture's down-light component. However, such design
approaches have the drawback that the extra lamps impair the
designer's ability to achieve a desired light distribution from a
given physical envelope and impose added burdens on lamp
maintenance providers who must stock and handle two different types
of lamps.
[0010] Conventional parabolic light fixture designs have several
negative features. One of these is reduced lighting efficiency.
Another is the so-called "cave effect," where the upper portions of
walls in the illuminated area are dark. In addition, the light
distribution of these fixtures often creates a defined line on the
walls between the higher lit and less lit areas. This creates the
perception of a ceiling that is lower than it actually is. Further,
when viewed directly at high viewing angles, a conventional
parabolic fixture can appear very dim or, even, off.
[0011] The present invention overcomes the above-described
disadvantages of light fixtures using brighter light sources by
providing a configuration that appears to a viewer as though it has
a source of lower brightness, but which otherwise permits the light
fixture to advantageously and efficiently distribute light
generated by the selected lamp, such as the exemplified T5 lamp.
The light fixture of the present invention reduces distracting
direct glare associated with high brightness light sources used in
direct or direct-indirect light fixtures.
SUMMARY OF THE INVENTION
[0012] The present invention relates to a light fixture, or
troffer, for efficiently distributing light emitted by a light
source into an area to be illuminated. In one general aspect of the
invention, the light fixture includes a reflector assembly that
supports the light source. The light fixture may also include a
lens assembly positioned with respect to a portion of the reflector
assembly to receive light emitted by the light source and
distribute it such that glare is further reduced. In a preferred
embodiment, the lens assembly receives and distributes
substantially all of the light emitted by the light source.
[0013] In one aspect, the reflector assembly of the light fixture
includes a base member that extends longitudinally between spaced
edges along a longitudinal axis. At least a portion of the base
member can form a reflective surface, which is preferably a curved
reflective surface. In one aspect, the reflector assembly supports
the light source such that the light source longitudinal axis is
substantially parallel to that of the base member. The light source
is preferably supported in a recessed portion of the reflector
assembly whereby high angle glare in directions transverse to the
longitudinal axis of the light fixture is blocked by the lower side
edges of the light fixture. The light source can be a conventional
lamp, such as, for example, a T5 lamp.
[0014] In a further aspect, the reflector assembly can comprise at
least one longitudinally extending hollow. In one exemplary aspect,
at least a portion of a cross-section of the hollow normal to the
longitudinal axis of the hollow has a generally curved shape that
extends inwardly to a central portion between respective first and
second hollow edges of the hollow. In another aspect, each hollow
may include a plurality or a series of longitudinally extending and
spaced male ridges. In one example, each male ridge comprises a
first surface and an adjoining second surface. The first surface of
each male ridge is preferably positioned at a first angle relative
to a reflector plane that bisects the longitudinal axis of the
hollow normal to the ceiling plane. In this aspect, it is
contemplated that the first angle is an acute angle such that each
first surface faces substantially inwardly toward the reflector
plane. In another aspect, each second surface is positioned at a
second angle relative to the reflector plane that is greater than
the first angle. For each respective male ridge, in one exemplary
aspect, the second surface can be positioned closer than the first
surface to the reflector plane.
[0015] In still another aspect, the lens assembly includes a lens
that has a first end edge, an opposed second end edge, and a
central lens portion that extends longitudinally between the first
and second end edges. In one aspect, the lens has a lens
longitudinal axis that is generally parallel to the light source
longitudinal axis. The central portion of the lens has a prismatic
surface that defines a face that can be oriented toward or away
from the light source. In one aspect, the central lens portion is
curved and can have a concave, convex, or planar shape in
cross-section. In an alternative aspect, the lens assembly may
include a diffuser inlay that is positioned in substantially
overlying registration with a portion of the face of the central
lens portion that faces the light source.
[0016] In one embodiment, the prismatic surface of the central lens
portion is concave relative to the light source. At least a portion
of the prismatic surface defines an array of contiguous and
parallel prismatic elements. In one example, each prismatic element
extends generally longitudinally and substantially between the
first and second edges of the lens. In one example, the prismatic
elements each have a curved surface that subtends an angle, in a
transverse vertical plane, of about and between 80.degree. to
120.degree. with respect to their center of curvature.
[0017] The lens is preferably detachably secured to a portion of
the reflector assembly in overlying registration with the light
source. In one aspect, a portion of the reflector assembly and a
portion of the lens substantially enclose the light source so that,
to an external viewer, the light source is substantially hidden
from view. In one example, the array of linear extending prismatic
elements presents to the external viewer an array of spaced,
longitudinally extending shadows, or dark stripes, on the lens.
Thus, the lens assembly of the present invention provides an
aesthetically more pleasing appearance as well as efficiently
distributing the light generated by the light source onto portions
of the reflective surfaces of the reflector assembly and onto the
desired area to be illuminated.
[0018] The lens assembly and reflector assembly of the present
invention increase the light efficiency of the light fixture and
diffuse the light relatively uniformly, which minimizes the "cave
effect" commonly noted in areas using conventional parabolic light
fixtures in the ceiling. In one embodiment, the light fixture or
troffer of the present invention results in a luminare efficiency
that is greater than 80%, preferably.
BRIEF DESCRIPTION OF THE FIGURES
[0019] These and other features of the preferred embodiments of the
invention will become more apparent in the detailed description in
which reference is made to the appended drawings wherein:
[0020] FIG. 1 is an exploded top perspective view of one embodiment
of the light fixture of the present invention.
[0021] FIG. 2 is an exploded bottom perspective view of the light
fixture of FIG. 1.
[0022] FIG. 3 is a bottom perspective view of the light fixture of
FIG. 2.
[0023] FIG. 4 is a cross-sectional view of the light fixture of
FIG. 3, taken along line 4-4.
[0024] FIG. 5A is a cross-sectional view of the light fixture of
FIG. 3, taken along line 5-5.
[0025] FIG. 5B is a cross-sectional view of one embodiment of the
light fixture, showing the central lens portion having a concave
shape.
[0026] FIG. 5C is a cross-sectional view of one embodiment of the
light fixture, showing at least a portion of the central lens
portion having a flat shape.
[0027] FIG. 6 is an exploded bottom perspective view of a second
embodiment of the light fixture of the present invention.
[0028] FIG. 7 is a partial top perspective view of a housing of the
light fixture showing one embodiment of a closure plate releaseably
connected to a port defined within a ballast enclosure.
[0029] FIG. 8 is an exploded bottom perspective view of one
embodiment of a lens assembly of the light fixture of the present
invention showing an elongated lens and a diffuser inlay.
[0030] FIG. 9 is a cross-sectional view of the lens assembly of
FIG. 8, taken along line 9-9.
[0031] FIG. 10 is an enlarged partial cross-sectional view of the
lens assembly of FIG. 8, showing one embodiment of an array of
prismatic elements disposed on a surface of the lens.
[0032] FIG. 11 is an enlarged partial cross-sectional view of the
lens assembly, showing an alternative embodiment of the array of
prismatic elements.
[0033] FIGS. 12 and 13 are enlarged partial cross-sectional views
of the lens assembly, showing additional alternative embodiments of
the array of prismatic elements.
[0034] FIG. 14 shows an enlarged partial cross-sectional view of
one embodiment of the lens assembly of the present invention with
the diffuser inlay in registration with a portion of the prismatic
surface of the lens.
[0035] FIG. 15 is a partial cross-sectional view of the light
fixture of FIG. 3, taken along line 15-15, showing exemplary paths
of light emitted from a high-intensity light source housed within
the light fixture above the ceiling plane.
[0036] FIG. 16 shows illumination test results for an exemplary
prior art 3-lamp T8 parabolic troffer.
[0037] FIG. 17 shows illumination test results for an exemplary
2-lamp T5 light fixture of the present invention.
[0038] FIG. 18 shows an exemplary path of a reverse ray of light,
in a vertical plane transverse to the longitudinal axis of the
light fixture, entering a face of the lens oriented away from the
light source.
[0039] FIG. 19 shows an exemplary path of a reverse ray of light,
in a vertical plane transverse to the longitudinal axis of the
light fixture, being rejected out of a face of the lens that is
oriented away from the light source.
[0040] FIG. 20 shows an exemplary path of a reverse ray of light,
in a vertical plane parallel to the longitudinal axis of the light
fixture, entering the face of the lens and being rejected out of
the face of the lens, the face being oriented away from the
light.
[0041] FIG. 21 is a perspective view of the exemplary path of a
reverse ray of light.
[0042] FIG. 22 is an exemplified schematic cross-sectional view of
a reflector assembly comprising a pair of longitudinally extending
hollows, each hollow having a plurality of longitudinally extending
male ridges, each male ridge having a first surface and an
adjoining second surface.
[0043] FIG. 23A is an enlarged partial schematic cross-sectional
view of the portion of the reflector housing of FIG. 22 taken along
the designated cut line.
[0044] FIG. 23B is an exemplified enlarged cross-sectional view of
the reflector housing of FIG. 22, showing the respective first and
second surfaces of the male ridges on a curved portion of the
hollow.
[0045] FIG. 23C is an exemplified enlarged cross-sectional view of
the reflector housing of FIG. 22, showing the pattern transition of
the respective first and second surfaces of the male ridges.
[0046] FIG. 24A is an enlarged partial cross-sectional view of a
hollow of the reflector assembly of FIG. 22, showing a first
embodiment of the pattern transition of the respective first and
second surfaces of the male ridges thereon.
[0047] FIG. 24B is an enlarged partial cross-sectional view of a
hollow of the reflector assembly of FIG. 22, showing a second
embodiment of the pattern transition of the respective first and
second surfaces of the male ridges thereon.
[0048] FIG. 24C is an enlarged partial cross-sectional view of a
hollow of the reflector assembly of FIG. 22, showing a third
embodiment of the pattern transition of the respective first and
second surfaces of the male ridges thereon.
DETAILED DESCRIPTION OF THE INVENTION
[0049] The present invention is more particularly described in the
following exemplary embodiments that are intended as illustrative
only since numerous modifications and variations therein will be
apparent to those skilled in the art. As used herein, "a," "an," or
"the" can mean one or more, depending upon the context in which it
is used. The preferred embodiments are now described with reference
to the figures, in which like reference characters indicate like
parts throughout the several views.
[0050] Ranges may be expressed herein as from "about" one
particular value, and/or to "about" another particular value. When
such a range is expressed, another embodiment includes from the one
particular value and/or to the other particular value. Similarly,
when values are expressed as approximations, by use of the
antecedent "about," it will be understood that the particular value
forms another embodiment.
[0051] Referring to FIGS. 1-6, a light fixture 10 or troffer of the
present invention for illuminating an area includes a reflector
assembly 20 for housing a linear light source 12. The light source
extends along a light source longitudinal axis between a first end
14 of the light source and a spaced second end 16 thereof. Light
emanating from the light source 12 is diffused by a lens assembly
100 that is positioned between the light source 12 and the area to
be illuminated. The light source 12 may be a conventional
fluorescent lamp, and in one aspect, the light source 12 can be a
conventional T5 lamp.
[0052] The reflector assembly 20 of the light fixture includes an
elongated base member 22 that has a first end edge 24, a spaced
second end edge 26, a first longitudinally extending side edge 28
and an opposed second longitudinally extending side edge 29. The
base member 22 further has a base surface 30 extending along a base
longitudinal axis. The base member can be formed from a single
piece of material or from a plurality of adjoined pieces. As one
will appreciate, the reflector assembly can be formed from any
code-compliant material. For example, the base member can be formed
from steel.
[0053] A portion of the base surface 30 of the base member 22 forms
at least one longitudinally extending hollow 32 that extends
inwardly in the transverse dimension with respect to and away from
the respective first and second longitudinally extending side
edges. Each hollow 32 has a first hollow edge 34 and a second
hollow edge 36 and extends inwardly toward a central portion 38
defined by and between the respective first and second hollow edges
34, 36. The central portion defines a longitudinally extending
trough 40 that extends inwardly away from the surface of the hollow
32. At least a portion of each hollow 32 preferably forms a
reflective surface 33 extending between central portion 38 and a
respective one of the first and second hollow edges 34, 36. In one
embodiment, at least a portion of a section of each hollow 32
normal to the base longitudinal axis has a generally curved shape
such that such that portions of the hollow 32 form a generally
curved reflective surface 35 for diffusely reflecting light
received from the lens into the architectural space in a desired
pattern. In one embodiment, the transverse section of the hollow
can have a conventional barrel shape. In an alternative embodiment,
a portion of each hollow 32 can have at least one planar
portion.
[0054] In one aspect, at least a portion of the hollow of the base
surface 30 of the base member can be painted or coated with a
reflective material or formed from a reflective material. The
reflective material may be substantially glossy or substantially
flat. In one example, the reflective material is preferably matte
white to diffusely reflect incident light.
[0055] The central portion 38 of the light fixture is preferably
symmetrically positioned with respect to the first and second
hollow edges 34, 36. The light fixture 10 of the present invention
can include one or more hollows 32 that each houses a light source
12, as shown in FIG. 6. For example, in a light fixture having a
single hollow, the first and second hollow edges 34, 36 of the
hollow would extend generally to the respective longitudinally
extending side edges 28, 29 of the base member 22. In an
alternative example, in which the light fixture 10 has two hollows,
the base member 22 defines a pair of adjoining, parallel hollows.
Here, a first hollow edge 34 of a first hollow 32' extends
generally to the first side edge 28 of the base member, and a
second hollow edge 36 of a second hollow 32'' of the pair of
hollows extends generally to the second side edge 29 of the base
member. The second hollow edge 36 of the first hollow 32' and the
first hollow edge 34 of the second hollow 32'' are adjoined in one
example. Alternatively, the second hollow edge 36 of the first
hollow 32' and the first hollow edge 34 of the second hollow 32''
are positioned proximate or near each other.
[0056] In one aspect, at least a portion of the base surface 30 of
the base member 22, preferably at least a portion of the reflective
surface 33 thereof, has a plurality of male ridges 37 formed
thereon that extend longitudinally between the ends of the base
member. In an alternative aspect, at least a portion of the base
surface 30 of the base member, preferably at least a portion of the
reflective surface 33 thereof, has a plurality of female grooves 39
formed thereon that extend longitudinally between the ends of the
base member. Alternatively, the ridges or grooves extend at an
angle with respect to the longitudinal axis of the base member. For
example, the male ridges or female grooves may extend transversely
with respect to the base longitudinal axis (i.e., extending between
the respective first and second longitudinally extending side edges
28, 29 of the base member). In another aspect, each male ridge or
female groove 37, 39 can extend substantially parallel to an
adjoining male ridge or female groove. The ridges 37 or grooves 39
formed on the hollow 32 provide a diffusely reflecting surface.
[0057] In an additional aspect, and referring now to FIGS. 22-24C,
at least a portion of the hollow 32 normal to a longitudinal axis
of the hollow has a generally curved, for example concave, shape
that extends inwardly toward the central portion 38 (FIG. 2)
defined by and between the respective first and second hollow edges
34, 36. In this aspect, each hollow 32 includes a plurality, which
may be provided as a series, of spaced male ridges 37 that extend
in the longitudinal direction of the hollow, each ridge comprising
a first surface 200 and an adjoining second surface 210. In one
aspect, each first surface 200 is positioned at a first angle p
relative to a reflector plane that bisects the longitudinal axis of
the hollow normal to the ceiling plane with respect to which the
light fixture is positioned. If desired, and as shown in FIG. 22,
the light fixture can comprise a pair of longitudinally extending
hollows 32', 32'' that are each positioned such that the respective
reflector planes thereof extend substantially parallel to each
other.
[0058] In one aspect, and referring to FIG. 23A, a pattern
transition between the respective first and second surfaces of the
plurality of male ridges can be substantially at the center of the
hollow of the reflector housing. It is also contemplated, in an
alternative embodiment, that portions of the hollow would not have
male ridges defined therein. In this aspect, the transition could
occur at any desired location on the hollow.
[0059] Portions of the reflector housing prior to its being formed
into the reflector housing that is illustrated in FIG. 22 are shown
in FIGS. 24A-C. In FIG. 24A, the pattern transition is exemplarily
shown substantially at the center of one hollow of the pair of
adjoining and longitudinally extending hollows 32', 32'' of the
reflector assembly. In FIG. 24B, the pattern transition is
exemplarily shown substantially at the respective edges of the
adjoining hollows 32', 32'' of the reflector assembly. Similar to
FIG. 24A, the pattern transition is exemplarily shown substantially
at the center of one hollow of the pair of adjoining and
longitudinally extending hollows 32', 32'' of the reflector
assembly in FIG. 24C.
[0060] In another aspect, the first angle .rho. is an acute angle
(FIGS. 23A-23B) such that each first surface 200 faces
substantially inwardly toward the aforementioned reflector plane.
In yet another aspect, each second surface 210 is positioned at a
second angle .sigma. relative to the reflector plane that is
greater than the first angle .rho. of an adjoining first surface
200, as shown in FIGS. 23A and B. In this aspect, relative to the
reflector plane, the second surface 210 of each respective male
ridge is positioned closer to the reflector plane than is the first
surface 200 of the respective ridges.
[0061] In another aspect, and as shown in FIG. 23B, the second
angle .sigma. of the second surfaces 210 of at least a portion of
the plurality of male ridges 37 can be positioned at an acute angle
such that the second surfaces of the respective ridges face
substantially inwardly toward the reflector plane. In another
aspect, and as shown in FIG. 23A, the second surfaces 210 of at
least some of the respective male ridges can be positioned at an
obtuse second angle such that the respective second surfaces faces
substantially outwardly relative to the reflector plane.
[0062] In a further aspect, and as exemplarily shown in FIG. 24A,
the second surface 210 of each male ridge has a cross-sectional
length I.sub.2 that is less than the cross-sectional length I.sub.1
of the first surface 200. In one example, the cross-sectional
length I.sub.2 of the second surface is between about 30 and 50
percent of the cross-sectional length of the first surface I.sub.1,
including the additional percentage lengths of 35, 40 and 45
percent.
[0063] In another exemplified aspect, the plurality of male ridges
37 comprises a pair of opposed sets of male ridges 37', 37'', which
can comprise a first set of male ridges and an opposed second set
of male ridges. In one aspect, the respective first and second sets
of male ridges extend outwardly, in opposed directions, from the
longitudinal axis of the reflector assembly toward their respective
first and second hollow edges 34, 36. In one aspect, the first set
of male ridges can be a substantial mirror image of the second set
of male ridges.
[0064] In operation, the light generated from the light source 12
that is incident on the respective portions of the first and the
second surfaces 200, 210 of the plurality of longitudinally
extending male ridges 37 form at least one, and preferably a
plurality of, longitudinally extending shadows in the reflector
assembly. Each longitudinally extending shadow has the appearance
of a dark stripe to an external viewer. One would appreciate that
the light generated from the light source that is incident on
portions of the respective first and the second surfaces of the
plurality of male ridges illuminates portions of the male ridges
and causes portions of the male ridges to be non-illuminated and
placed into shadow. In one aspect, it is contemplated that the
respective illuminated and non-illuminated portions of the male
ridges are positioned in alternating and adjoining relationship to
each other. Thus, to an external viewer, the non-illuminated
portions of the male ridges have the appearance of dark shapes
relative to the illuminated portions of the male ridges. If the
ridges have a generally elongate, longitudinal shape, the dark
shapes would have the appearance of a dark stripe.
[0065] A trough 40 is formed by a top surface 42, a first side
trough surface 44 and an opposed second side trough surface 46 is
provided for receiving the elongated light source 12. The trough
extends along an axis parallel to the longitudinal axis of the
light fixture. Each respective first and second side trough surface
has a lower edge 48 that is integral with a portion of the adjoined
hollow 32. In one example, the lower edges of the first and the
second trough surfaces are integral with the reflective surfaces 33
of the adjoined hollow. Each respective first and second side
trough surfaces defines a trough surface axis that extends in a
vertical plane normal to the base longitudinal axis of the base
member.
[0066] In one aspect, the trough surface axis of each of the first
and second trough surfaces 44, 46 respectively forms an angle
.theta. of about and between about 140.degree. to 90.degree. with
respect to the top surface 42 of the trough. More particularly, the
angle .theta. can be about and between about 135.degree. to
95.degree. with respect to the top surface of the trough. Still
more particularly, the angle .theta. can be about and between about
130.degree. to 100.degree. with respect to the top surface of the
trough. In another aspect, the angle .theta. formed between each of
the respective first and second trough surfaces and the top surface
of the trough can be substantially equal.
[0067] In one aspect of the invention, the light source 12 can be
positioned between the base surface of the base member and the lens
assembly. In another aspect of the invention, the light source 12
can be positioned within the trough 40 of the reflector assembly 20
such that the light longitudinal axis is positioned above a plane
that extends between the lower edges 48 of the respective first and
second trough surfaces. Alternatively, the light source 12 can be
positioned within the trough of the reflector assembly such that
the light source is positioned substantially about or above an
arcuate section that extends between the lower edges 48 of the
respective first and second trough surfaces 44, 46 and is an
arcuate continuation of the curvature of the curved reflective
surfaces 35 of the hollow. In this aspect, the radius of the
arcuate section can have substantially the same radius as the
curved portion of the hollow. If the curved reflective surfaces of
the hollow are parabolic, the arcuate section is a parabolic
extension of the parabolas of the curved reflective surface.
[0068] The reflector assembly 20 can also include a first end face
50 and an opposed second end face 52. Each of the end faces extends
upwardly away from a respective bottom edge 55 toward a top edge 54
of the light fixture. Each end face has a face longitudinal axis
that forms an obtuse angle with respect to the longitudinal axis of
the base member 22. In one aspect, the end faces 50, 52 are
positioned with respect to the base member such that a portion of
the top edge 54 of the end faces 50, 52 is positioned in
substantial overlying registration with portions of the base
surface 30. It is contemplated that at least a portion of the top
edge 54 can contact at least a portion of the base surface 30. In
another aspect, at least a portion of the top edge 54 is spaced
inwardly from the end edges 24, 26 of the base member. The angled
first and second end faces 50, 52 optically alter the apparent
perspective of the light fixture and aesthetically give the light
fixture a deeper appearance.
[0069] In one aspect, the face longitudinal axis of each of the
first and second end faces 50, 52 respectively forms an angle
.OMEGA. of about and between 95.degree. to 160.degree. with respect
to the base longitudinal axis of the base member 22. More
particularly, the face longitudinal axis of each of the first and
second end faces respectively forms an angle .OMEGA. of about and
between 100.degree. to 150.degree. with respect to the base
longitudinal axis. Still more particularly, the face longitudinal
axis of each of the first and second end faces respectively forms
an angle .OMEGA. of about and between 100.degree. to 135.degree.
with respect to the base longitudinal axis. In another aspect, the
face longitudinal axis of each of the first and second end faces
respectively forms an angle .OMEGA. of about 120.degree. with
respect to the base longitudinal axis. In yet another aspect, the
respective obtuse angles formed between the face longitudinal axis
of the first end face 50 and between the face longitudinal axis of
the second end face 52 and the base longitudinal axis of the base
member 22 are substantially equal.
[0070] Alternative shapes of the first and second end faces 50, 52
are contemplated. Each of the first and second end faces may be
substantially planar or non-planar. In the non-planar embodiments,
portions of the first and second end faces are curved. The curved
portions of the first and second end faces can be substantially
concave or substantially convex. Portions of the first and second
end faces can also have male ridges or female grooves formed
thereon. The male ridges or female grooves can be sized, shaped and
oriented to visually complement the male ridges or female grooves
on the base member 22, as described above.
[0071] The light fixture 10 of the present invention also includes
a housing 60 having a first end wall 62 and a second end wall 64.
In one aspect, the first end wall 62 is connected to a portion of
the first end edge 24 (FIG. 2) of the base member 22 and the second
end wall is connected to a portion of the second end edge 26 of the
base member 22. In this aspect, a portion of the bottom edge 55 of
the first end face 50 can be connected to a bottom portion 63 of
the first end wall 62 of the housing and a portion of a bottom edge
55 of the second end face 52 is also connected to a bottom portion
63 of the second end wall 64 of the housing. In one example, the
first end wall 62 and the first end face 50 can be formed integral
to each other. Similarly, the second end wall 64 and the second end
face 52 can be formed integral to each other. The first end wall 62
can be positioned substantially perpendicular to the base member 22
adjacent the first end edge of the base member. Similarly, the
second end wall 64 can be positioned substantially perpendicular to
the base member 22 adjacent the second end edge of the base
member.
[0072] In one aspect, an opening 56 is defined in each of the first
and second end faces 50, 52 that is configured to receive at least
a portion of a selected end 14, 16 of the light source 12 therein.
In this aspect, portions of the respective first and second end
faces 50, 52, portions of the respective first and second end walls
62, 64, and portions of the base surface 30 together define a
chamber 58 adjacent the respective top edges 54 of the first and
second end faces. The chamber 58 is in operative communication with
the opening 56 in the respective first and second faces 50, 52 and
is constructed and arranged to receive at least a portion of a
selected end 14, 16 of the light source therein. The brighter
conventional lamps, such as the exemplified T5 lamp, are typically
shorter and have an elongated dark portion proximate their ends
when compared to other conventional elongated fluorescent lamps,
such as, for example, conventional T8 and T12 lamps. Thus, in use,
the chambers prevent the darkened ends of the selected light source
from being visible through the lens assembly.
[0073] In one aspect, each chamber 58 is configured to mount an
electrical contact 59 or receptacle for detachably securing a
selected end of the light source thereto. In one example, the
electrical contact 59 is mounted onto a portion of the base surface
30 of the base member 22 that partially defines the chamber 58. It
is contemplated that the electrical contact 59 can be mounted to
any of the surfaces that define the chamber 58.
[0074] Referring to FIGS. 1 and 7, the housing of the light fixture
can also include at least one angled cover 65, illustrated as being
a pair of angled faces 65' and 65'', respectively. In one aspect,
each angled cover has a first panel 66 and a second panel 67 that
are connected to each other along a common, angled edge 68. Each
first panel 66 has a first side edge 70 and each second panel 67
has a second side edge 72. The first side edge 70 of the first
panel 66 is connected to a portion of the first longitudinal side
edge 28 of the base member 22. The second side edge 72 of the
second panel 67 is connected to a portion of the base top surface
31 of the base member 22. In one example, the first panel 66 of the
angled cover 65 is substantially perpendicular to the base member
22 adjacent the first longitudinally extending side edge 28 of the
base member. In another example, the first and second panels 66, 67
of the angled cover 65 are substantially perpendicular to each
other. In one aspect, the angled cover 65 extends between the first
and second end walls 62, 64 of the housing 60 such that portions of
the first angled cover, portions of the respective first and second
end walls 62, 64 and portions of the base top surface 31 together
define a first ballast enclosure 74' (FIG. 7).
[0075] The light fixture 10 also includes at least one conventional
light ballast 76 constructed and arranged for electrically
connecting the light source to an external power source. In one
aspect, the at least one ballast 76 is positioned within the
interior of the first ballast enclosure 74'. In order to access the
ballast, a portion of the first angled cover 65' of the housing 60
of the light fixture defines a first port 78' that is in
communication with the interior of the first ballast enclosure 74'.
In one aspect, the first port is positioned adjacent the angled
edge 68 of the first angled cover 65'. The housing 60 may also
include a first closure plate 79' that is constructed and arranged
for releasable connection to the first angled cover 65'. In a
closed position, the first closure plate is in substantial
registration with the first port 78' so that the ballast positioned
within the first ballast enclosure 74' can be selectively
enclosed.
[0076] Referring to FIG. 7, in one aspect, at least a portion of
the first port 78' is defined in a portion of the second panel 67
of the first angled cover 65'. In another aspect, at least a
portion of the first port 78' is defined in a portion of the first
panel 66 of the first angled cover 65'. In this latter example, the
defined portion of the first port 78' is spaced from the first side
edge 70 of the first panel 66 of the first angled cover a
predetermined distance. The predetermined distance is greater than
the height of a conventional ceiling panel or tile that would
typically abut the bottom portion of the light fixture. Because the
predetermined distance is greater than the conventional height of a
ceiling panel, the first closure plate 79' can therefore be removed
without binding onto the abutting ceiling panel or ceiling support
apparatus.
[0077] In an alternative example, a portion of the first port 78'
is defined in a portion of both the first and second panels 66, 67.
Here, the defined portion of the first port in the first panel is
spaced from the first side edge 70 of the first panel 66 of the
first angled cover 65' the predetermined distance, as discussed
above. In this example, portions of the first closure plate 79' are
positioned at an angle with each other that is complementary to the
angle formed between the first and second panels 66, 67 of the
first angled cover along angled edge 65.
[0078] The angled cover 65, as discussed above, can also include a
second angled cover 65'' (FIG. 11). In this example, the first side
edge 70 of the first panel 66 of the second angled cover 65'' is
connected to a portion of the second longitudinally extending side
edge 29 of the base member 22 and the second side edge 72 of the
second panel 67 of the second angled cover is connected to a
portion of the base top surface 31 of the base member. Similar to
the first angled cover, the second angled cover extends between the
first end wall 62 and the second end wall 64 of the housing 60 such
that portions of the first and second end walls 62, 64, portions of
the second angled cover 65'', and portions of the base top surface
31 together define a second ballast enclosure 74''. The second
ballast enclosure can remain empty or a second ballast 76'' can be
positioned within the interior of the second ballast enclosure as
the electrical demands of the use of the light fixture dictate. As
one will appreciate, the second ballast can be in electrical
communication with the light source and the external power
source.
[0079] Accordingly, and still referring to FIG. 1, a portion of the
second angled cover can define a second port 78'' adjacent the
angled edge 68 that is in communication with the second ballast
enclosure 74''. A second closure plate 79'' is provided that is
constructed and arranged for releasable connection to the second
angled panel 65'' such that, in a closed position, the second
closure plate 79'' is in substantial registration with the second
port. Thus, the second ballast positioned in the second ballast
enclosure 74'' can be selectively enclosed.
[0080] In one aspect, therefore, at least a portion of the second
port 78'' is defined in a portion of the first panel 66 of the
second angled cover 65'' and is spaced from the first side edge 70
of the first panel 66 the predetermined distance, as discussed
above, for clearance from abutting ceiling panels. Alternatively,
at least a portion of the second port 78'' is defined in a portion
of the second panel 67 of the second angled cover. In one other
embodiment, at least a portion of the second port 78'' is defined
in the first panel 66 of the second angled cover (spaced from the
first side edge 70 of the first panel the predetermined distance)
and at least a portion of the second port 78'' is defined in a
portion of the second panel 67 of the second angled cover 65''.
Here, portions of the second closure plate 79'' are positioned at
an angle with respect to each other that is complementary to the
angle formed between the first and second panels 66, 67 of the
second angled cover 65'' along angled edge 68.
[0081] In an alternative embodiment, suitable for retrofit
applications, the housing can be a pre-existing housing that, for
example, is conventionally mounted therein a ceiling. In this
embodiment, the reflector assembly of the present invention is
connected to the pre-existing housing. In one aspect, at least a
portion of the base member defines an access port. A movable cover,
not illustrated, is provided in or on the reflector assembly that
can be configured to be opened and closed by an operator to access
a ballast that is disposed in an interior cavity, which is formed
between the back of the reflector assembly and portions of the
pre-existing housing.
[0082] In an alternative embodiment, the light fixture is suspended
from the ceiling. In this embodiment, the reflector assembly can be
connected to a housing that defines an interior cavity sized to
accept the electrical ballast therein. The housing is spaced from
the ceiling a predetermined distance and is mounted to the ceiling
via conventional suspension means. Alternatively, the ballast can
be mounted onto a portion of the surface of the base member that is
oriented towards the ceiling. Here, the base member is spaced from
the ceiling a predetermined distance and is mounted to the ceiling
via conventional mounting means.
[0083] As one will appreciate, it is contemplated that such a
suspended light fixture could include one or more hollows, as shown
in FIG. 6. In a suspended light fixture having a single hollow, the
respective first and second side edges of the hollow would extend
to the edges of the base member. In an example having a pair of
parallel hollows, the first hollow edge of a first hollow extends
to one side edge of the base member and the second hollow edge of
the second hollow edge extends to the other side edge of the base
member. In one aspect, the trough of the reflector assembly of the
suspended light fixture is integral with a portion of an adjoined
hollow. In another aspect, the reflector assembly of the suspended
light fixture includes at least one end face that is positioned at
an obtuse angle with respect to the base member of the reflector
assembly.
[0084] Referring to FIGS. 1-6 and 8-15, the lens assembly 100 of
the present invention is constructed and arranged to direct light
emitted by the light source 12 onto the area to be illuminated. A
basic function of the lens assembly 100 is to diffuse the light
from the light source 12 to effectively hide the light source 12
itself from view while reducing its brightness. Thus, one function
of the lens assembly is to effectively become the source of light
for the light fixture. This is accomplished in the preferred
embodiment by providing the lens 1 10 of the lens assembly with an
array 120 of longitudinally extending prismatic elements 122 with
short focal lengths. Because of the short focal lengths of the
prismatic elements, the light from the light source is focused to
parallel images very close to the surface of the lens at large
angles of convergence. Because of the large angles of convergence,
the images overlap and the light is essentially diffused. The
diffused light is then either directed onto the surface to be
illuminated without further reflection or is reflected by the
reflective surfaces of the hollow 32. Thus, the lens assembly
provides a diffuse source of lowered brightness.
[0085] As discussed above, the light source 12 is mounted in the
trough and is recessed with respect to the side edges of the
reflector assembly. This allows the lens 110 to be placed higher in
the light fixture and provides geometric control of high-angle rays
emanating from the lens in the transverse direction. Thus, light
rays produced at high viewing angles are physically blocked by the
bottom longitudinally extending side edges 28, 29 of the light
fixture, which prevents glare at high angles in that transverse
direction. The light fixture of the invention controls glare in the
longitudinal direction, however, optically.
[0086] High angle glare is reduced in the longitudinal direction as
illustrated in FIGS. 18-21 and as described below. Thus, in this
aspect, the light fixture of the invention prevents glare at high
viewing angles through two mechanisms, geometrically in the
transverse direction and optically in the longitudinal
direction.
[0087] In one aspect, the lens assembly 100 includes a lens 110
having a first end edge 112, an opposed second end edge 113, and a
central lens portion 114 that extends between the first and second
edges. The central lens portion 114 has a lens longitudinal axis
that extends between the first and second end edges. In one
example, the lens longitudinal axis is generally parallel to the
light source longitudinal axis of the light source 12. In use, the
lens 110 of the lens assembly is positioned with respect to the
reflector assembly 20 of the light fixture such that substantially
all of the light emitted by the light source 12 passes through the
lens 110 prior to impacting portions of the reflective surfaces 33
of the reflector assembly and/or prior to being dispersed into the
surrounding area.
[0088] The lens 110 can be made from any suitable, code-compliant
material such as, for example, a polymer or a plastic. For example,
the lens 110 can be constructed by extruding pellets of
meth-acrylate or polycarbonates into the desired shape of the lens.
The lens 110 can be of a clear material or translucent material. In
another aspect, the lens can be colored or tinted.
[0089] Referring to FIGS. 5A-5C, the central lens portion 114 of
the lens has a prismatic surface 116 on a face 118 of the central
lens portion that is either spaced from and facing toward the light
source 12 (FIG. 5A) or, alternatively, spaced from and facing away
from the light source 12 (FIG. 5B). In one aspect of the invention,
the central lens portion 114 is curved in cross-section such that
at least a portion of the face 118 of the central lens portion has
a concave or convex shape relative to the light source. In an
alternative embodiment, at least a portion of the central lens
portion 114 is planar in cross-section.
[0090] In one aspect, the lens 110 is positioned within the
reflector assembly so that it is recessed above a substantially
horizontal plane extending between the first and second
longitudinally extending side edges 28, 29 thereof. In a further
aspect, the lens is recessed within the reflector assembly such
that a plane bisecting one of the respective first and second
longitudinally extending side edges and a tangential portion of the
lens is oriented at an acute angle y to the generally horizontal
plane extending between the first and second longitudinally
extending side edges 28, 29. In one aspect, the acute angle y is
about and between 3.degree. to 30.degree.. More particularly, the
acute angle .gamma. is about and between 05.degree. to 20.degree..
Still more particularly, the acute angle .gamma. is about and
between 10.degree. to 15.degree..
[0091] The recessed position of the lens assembly within the
reflector assembly provides for high angle control of light emitted
by the light fixture in a vertical plane normal to the base
longitudinal axis of the base member. In use, an observer
approaching the ceiling mounted light fixture of the present
invention from the side (i.e., from a direction transverse to the
base longitudinal axis) would not see the lens assembly until they
passed into the lower viewing angles. In effect, portions of the
reflector assembly act to block the view of the lens assembly from
an observer at the higher viewing angles (i.e., the viewing angles
closer to the horizontal ceiling plane).
[0092] In one aspect, as shown in FIGS. 8-17, the prismatic surface
116 of the lens defines an array of linearly extending prismatic
elements 120. In one example, each prismatic element 122 of the
array 120 can extend substantially longitudinally between the first
and second edge end edges 112, 114 of the lens. Alternatively, each
prismatic element 122 of the array can extend linearly at an angle
relative to the lens longitudinal axis. For example, each prismatic
element can extend generally transverse to the lens longitudinal
axis. In a further aspect, each prismatic element 122 can have
substantially the same shape or, alternatively, can vary in shape
to cause differing visual effects on an external observer, lighting
of the hollow surface, or light distribution to the room. In one
aspect, each prismatic element has a portion that is rounded or has
a curved surface.
[0093] In one aspect, in section normal to the lens longitudinal
axis, each prismatic element has a base 124 and a rounded apex 126.
Each prismatic element extends toward the apex 126 substantially
perpendicular with respect to a tangent plane that extends through
the base 124. In one aspect, an arcuate section or curved surface
128, normal to the lens longitudinal axis, of each prismatic
element 122 subtends an angle .beta. of about and between
85.degree. to 130.degree. with reference to the center of curvature
of the arcuate section. More particularly, the arcuate section 128
of each prismatic element forms an angle .beta. of about and
between 90.degree. to 120.degree.. Still more particularly, the
arcuate section 128 forms an angle .beta. of about and between
95.degree. to 110.degree.. In another aspect, the arcuate section
128 forms an angle .beta. of about 100.degree..
[0094] In one aspect, the arcuate section 128 extends from a first
cusp edge 130 of the prismatic element 122 to an opposed second
cusp edge 132. In this example, adjoining prismatic elements are
integrally connected at a common cusp edge 130. Alternatively, the
arcuate section 128 may be formed in a portion of the apex 126 of
the prismatic element 122, such that adjoining prismatic elements
are integrally connected along the common edge 133. In this
example, portions of the prismatic element 122 extending between
the arcuate section and the common edge 133 can be planar or
non-planer, as desired. It should be understood that other
configurations and shapes are contemplated where the cross section
of the optical elements is not strictly circular, and includes, for
example, parabolic, linear, or other shapes.
[0095] In one aspect, the base 124 of each prismatic element 122
has a width (w) between its respective common edges of about and
between 0.5 inches to 0.01 inches. More particularly, the base of
each prismatic element has a width between its respective common
edges of about and between 0.3 inches to 0.03 inches. Still more
particularly, the base of each prismatic element has a width
between its respective common edges of about and between 0.15
inches to 0.05 inches.
[0096] In another aspect, as shown in FIG. 11, a section of the
array of prismatic elements 120 has a shape of a continuous wave.
The section can be normal to the lens longitudinal axis. In one
aspect, the shape of the continuous wave is a periodic waveform
that has an arcuate section 128 formed in both the positive and
negative amplitude portions of the periodic waveform (i.e., two
prismatic elements are formed from each single periodic waveform).
The period of the periodic waveform can be substantially constant
or may vary along the array of prismatic elements. In one aspect,
the periodic waveform is a substantially sinusoidal waveform. In
this example, the common cusp "edge" 130,132 between the two
prismatic elements 122 forming from each periodic waveform occurs
at the transition from positive/negative amplitude to
negative/positive amplitude.
[0097] As shown in FIG. 11, the arcuate section 128 of each
prismatic element 122 within each of the positive and negative
amplitude portions of the periodic waveform subtends an angle
.lamda. of about and between 85.degree. to 130.degree. with
reference to a center of curvature of the arcuate section. More
particularly, the arcuate section 128 of each prismatic element
within each of the positive and negative amplitude portions of the
periodic waveform forms an angle .lamda. of about and between
90.degree. to 120.degree.. Still more particularly, the arcuate
section 128 of each prismatic element within each of the positive
and negative amplitude portions of the periodic waveform forms an
angle A of about and between 95.degree. to 110.degree. with respect
to the base longitudinal axis. In another aspect, the arcuate
sections 128 within each of the positive and negative amplitude
portions of the periodic waveform form an angle .lamda. of about
100.degree..
[0098] Still referring to FIG. 11, in one aspect, the period P of
each prismatic element is about and between 1.0 inches to 0.02
inches. More particularly, the period P of each prismatic element
is about and between 0.6 inches to 0.06 inches. Still more
particularly, the period P of each prismatic element is about and
between 0.30 inches to 0.10 inches.
[0099] The lens 110 of the light assembly 100 is configured for
detachable connection to the light fixture 10 or troffer. In one
aspect, when positioned relative to the base member 22, the central
lens portion 114 of the lens assembly can extend generally parallel
to the light source longitudinal axis and generally symmetric about
a plane that extends through the light source longitudinal axis. In
one other aspect, the plane of symmetry extends through the area
desired to be illuminated. In one example, the lens 110 is
configured for detachable connection to a portion of the base
surface 30 of the reflector assembly 20. In one particular example,
the lens 110 is configured for detachable connection to a portion
of the trough 20 defined in the base member 22.
[0100] In one aspect, the elongated lens 110 has a first arm 140
(FIG. 9) that is connected to a first lens edge 115 of the central
lens portion 114 and a second arm 142 that is connected to a second
lens edge 117 of the central lens portion 114. A portion of the
each respective first and second arm 140, 142 is configured to be
detachable secured to portions of the trough 40. In one example, a
portion of the first arm 140 is configured to be detachably secured
to a portion of the first side trough surface 44 (FIG. 5A) and a
portion of the second arm 142 is configured to be detachably
secured to a portion of the second side trough surface 46.
[0101] In one example, each of the first and second side trough
surfaces 44, 46 has at least one male protrusion 45 FIG. 6), for
example, a tab, extending inwardly into the interior of the trough
40. Each of the first and second arms 140, 142 of the lens 110 has
an end portion 144 that is sized and shaped for detachable
engagement with the at least one male protrusion 45 in each of the
respective first and second trough surfaces. Alternatively, each of
the first and second side surfaces 44, 46 can define at least one
slot 47 (FIG. 2) that is configured to complementarily engage a
male protrusion 145 projecting from the end portion 144 of each of
the respective first and second arms 140, 142 of the lens. In use,
the lens 110 may be removed from the reflector housing by applying
force to the respective first and second lens edges 115, 117 of the
central lens portion 114. The application of force causes the
central lens portion 114 to bend and, resultantly, causes the
respective end portions 144 of the first and second arms 140, 142
to move toward each other. Removal of the applied force allows the
lens 110 to return toward its unstressed shape and allows the
respective end portions 144 of the first and second arms 140, 142
to move away from each other.
[0102] In one aspect, each of the first and second arms of the lens
has a bottom portion 146 (FIG. 9) that is connected to the
respective first and second lens edges 115, 117 and extends toward
the end portions 144 of the respective arms 140, 142. The bottom
portion 146 can be planar or non-planer in shape. In one example,
the bottom portion 146 extends substantially between the first end
edge 112 and the second end edge 113 of the lens.
[0103] As shown in FIG. 5A, in one example, in use, whereby the
lens 110 is detachably secured to the trough 40 of the reflector
assembly 20, a portion of the bottom portion 146 of each of the
first and second arms of the lens is detachably positioned adjacent
to a portion of the respective lower edges 48 of the first and
second side trough surfaces 44, 46. In one aspect of the invention,
a portion of the bottom portion 146 of each of the first and second
arms 140, 142 of the lens 110 is positioned at an acute angle with
respect to the reflective surface 33 of the hollow 32 adjacent the
respective lower edge 48 of the first and second trough surfaces
44, 46. In this example, the portion of the bottom portion 146 of
each of the first and second arms of the lens overlies a portion of
the reflective surface 33 of the hollow 32 adjacent the respective
lower edge 48 of the first and second trough surfaces. Here, the
distance between the respective first and second lens edges 115,
117 of the lens 110 is greater than the distance between the
respective lower edges 48 of the first and second side trough
surfaces 44, 46.
[0104] In the embodiment described immediately above, each of the
respective first and second lens edges 115, 117 is spaced from and
overlies a portion of the reflective surfaces 33 of the hollow 32.
Alternatively, and as shown in FIGS. 5B and 5C, the respective
first and second lens edges 115, 117 may be positioned adjacent a
portion of the respective lower edges 48 of the first and second
side trough surfaces 44, 46. In this particular embodiment, the
lens 110 generally does not overly a portion of the curved
reflective surface 33 of the hollow.
[0105] In one aspect, portions of the lens 110 that are positioned
adjacent the surface of the reflective assembly 20 are sized and
shaped to be in close overlying registration with portions of the
reflector assembly when the lens 110 is detachably secured to the
reflector assembly 20. For example, each of the respective first
and second ends 112, 113 of the lens are sized and shaped to be
positioned adjacent to and in close overlying registration with
portions of the reflector assembly 20, such as, for example,
portions of the first and second end faces, if used. Thus, the
light source 12 housed within the trough 40 of the reflector
assembly 20 is substantially enclosed when the lens 110 is
detachably secured to the reflective assembly.
[0106] In one aspect, when the lens assembly is positioned within
the reflector assembly, the light source is positioned below a
plane bisecting the respective first or second longitudinally
extending side edges 28, 29 of the base member and the adjacent
respective first or second lens edges 115, 117. In this example,
the relative position and shape of the reflector assembly and the
lens assembly would prevent an observer, approaching the light
fixture from a direction transverse to the base longitudinal axis,
from viewing the light source through the bottom portion of the
respective first or second arms of the lens.
[0107] The lens assembly 100 can also include a conventional
diffuser inlayl 50 (FIG. 9), such as, for example, a OptiGrafix.TM.
film product, which is a diffuser film that can be purchased from
Grafix.RTM. Plastics. The diffuser inlay 150 can be pliable or
fixed in shape, transparent, semi-translucent, translucent, and/or
colored or tinted. In one example, the diffuser inlay 150 has
relatively high transmission efficiency while also scattering a
relatively high amount of incident light to angles that are nearly
parallel to its surface. In one aspect, the diffuser inlay is
positioned between a portion of the face 118 of the central lens
portion and the light source 12. In another aspect, the diffuser
inlay is sized and shaped for positioning in substantial overlying
registration with the portion of the face 118 of the central lens
portion 114 that is oriented toward the light source 12.
[0108] The diffuser inlay 150 may be positioned in substantial
overlying registration with a portion of the prismatic surface 116
of the central lens portion 114. In one aspect of the present
invention, there is a gap 152 formed between portions of the two
adjoining rounded prismatic elements 122 extending between the
respective apexes of the two adjoined prismatic elements and the
bottom face 151 of the diffuser inlay 150. The formed gap enhances
the total internal refection capabilities of the lens assembly
100.
[0109] Referring to FIGS. 16-21, the lens assembly 100 and
reflector assembly 20 of the present invention increase the light
efficiency of the light fixture 10 and diffuse the light relatively
uniformly so that the "cave effect" commonly noted in areas using
conventional parabolic light fixtures in the ceiling are minimized.
In one embodiment, the light fixture 10 or troffer of the present
invention results in a luminare efficiency that is greater than
about 80%, preferably greater than about 85%. The efficiency of the
light fixture 10 is measured by using a goniophotometer to compare
the light energy from the light fixture at a given angle with the
light from an unshielded light source, as specified in the
application testing standard. The test results for an exemplary
light fixture of the present invention and comparable results for a
conventional parabolic light fixture are included in FIGS. 16 and
17. The light fixture of the present invention has reduced light
control relative to conventional parabolic fixtures to provide a
lit space (particularly the walls) with a bright appearance while
still maintaining adequate control and comfortable viewing for
today's office environment.
[0110] The light fixture 10 of the present invention has a low
height profile that allows for easy integration with other building
systems and installations in low plenum spaces. In one aspect, the
height profile of the light fixture is about or below 5 inches.
More particularly, the height profile of the light fixture is about
or below 4 inches. In another aspect, the height profile of the
light fixture is about 3.25 inches.
[0111] In one embodiment of the lens assembly 100 discussed above,
the central lens portion 114 of the lens 110 has a concave face 118
oriented toward the light source 12 when the lens 110 is detachably
secured to and within a portion of the reflector assembly 20. The
array of male rounded prismatic elements 120 can be extruded along
the length of the lens 110. In use, the lens of the present
invention design has a striped visual characteristic to an external
observer when back lit. These "stripes" provide for visual interest
in the lens 110 and may be sized and shaped to mirror any ridges or
grooves disposed in portions of the reflective surfaces 33 of the
hollow 32 of the reflector assembly 20. The "stripes" also help to
mitigate the appearance of the image of the lamp (the light source)
by providing strong linear boundaries that breakup and distract
from the edges of the lamp against the less luminous trough 40 of
the reflector assembly 20. In addition, the "stripes" allow for the
light fixture 10 of the present invention to provide high angle
light control in vertical planes that are substantially parallel to
the longitudinal axis of the light fixture.
[0112] In a preferred embodiment, a primary function of the lens is
to optically reduce the brightness of the light source. In
addition, the lens reduces the brightness of the light source even
further at higher viewing angles in the longitudinal direction by
the optical phenomenon of total internal reflection. This allows
the efficient use of light sources of higher brightness while
nevertheless reducing glare at high viewing angles.
[0113] It will be appreciated that the light fixture of the
invention utilizes a unique combination of features to reduce
high-angle glare in the transverse and longitudinal directions. In
the transverse direction, high angle glare is controlled primarily
by the geometric relationship between the lamp and the reflector
assembly of the light fixture, as discussed above, while in the
longitudinal direction, high angle glare is controlled primarily by
the lens optically. In the preferred embodiment, the lens itself
essentially becomes the light source, which effectively reduces
lamp brightness in both the transverse and longitudinal directions
optically, to further reduce glare associated with lamps of high
brightness.
[0114] Referring now to FIGS. 18-21, the optical creation of the
dark "stripes" in the lens is illustrated. A "reverse ray,"
"backward ray" or "vision ray" is a light ray that originates from
a hypothetical external viewer's eye and is then traced through the
optical system of the light fixture. Although there is no physical
equivalent, it is a useful construct in predicting how a particular
optical element will look to an observer. In the present invention,
on at least one side at the respective common cusp edges 130, 132,
133 of adjoining rounded prismatic elements 122, there exists a
sufficiently large angle of incidence .omega. relative to the
normal extending from the point of incidence of the reverse ray at
the lens to air interface that a reverse ray will undergo total
internal reflection. In one aspect, the angle of incidence .omega.
is at least about 40.degree.. More particularly, the angle of
incidence .omega. is at least about 45. Still more particularly,
the angle of incidence .omega. is at least about 50.degree.. In
effect, the array of prismatic elements acts as an array of partial
light pipes.
[0115] Each rounded prismatic element 122 has a sufficiently large
angular extent such that some total internal reflection at each
common cusp edge is assured regardless of viewing angle. In one
aspect, since each curved surface or arcuate section 128 of each
rounded prismatic element 122 is substantially circular, if a
reverse ray undergoes total internal reflection at one portion of
the arcuate section and is subsequently reflected to another
portion of the arcuate section, then total internal reflection will
also occur at the second point of incidence because the arcuate
section's geometry causes both interactions to have substantially
the same angle of incidence. Generally then, a reverse ray that
undergoes total internal reflection proximate a common cusp edge
133 will eventually exit the lens 110 out the same outer surface
through which it entered the lens and will terminate on a surface
or object in the room (as opposed to passing through the lens and
terminating on the light source or the trough of the reflector
assembly behind the lens).
[0116] The reverse ray is said to be "rejected" by the lens. This
means that the brightness an external viewer will perceive at the
common cusp edge 133 of adjoining rounded prismatic elements 122 is
the brightness associated with a room surface because any
real/forward light ray impinging on the viewer's eyes from this
part of the lens must have originated from the room or space.
Generally, the brightness of an object or surface in the room is
much lower than that of the light source or trough that is viewed
through the central portions of the arcuate sections 128 of each
prismatic element 122. This high contrast in brightness between the
common cusp edge 133 between adjoining rounded prismatic elements
122 and the central portion of the arcuate sections 128 of each
prismatic element 122 is so high that it is perceived, to the
external viewer, as dark stripes on a luminous background.
[0117] The linear array 120 of prismatic elements 1222 of the lens
assembly 100 optically acts in the longitudinal direction to reduce
high angle glare. This may be explained by considering a reverse
ray that is incident on a portion of the prismatic surface of the
lens proximate the common cusp edge 133 at the critical angle (the
minimum angle of incidence w) for total internal reflection of the
reverse ray. An observer viewing that portion of the lens (i.e.,
the portion of the area about the common cusp edge) would perceive
it as being "dark" relative to that adjacent "bright" portion of
the arcuate section proximate the rounded apex of each individual
prismatic element. The array of linear elements thus optically
controls the light emitted from the lamp in the longitudinal
direction.
[0118] In one example, as the lens 110 is viewed at higher and
higher viewing angles (as when the observer is further from the
light fixture) in a vertical plane parallel or near parallel to the
longitudinal axis of the base member, the striping effect on the
surface of the lens becomes more pronounced. This is a result of
the increase in that portion of the prismatic surface of the lens
that undergoes total internal reflection and creates the dark
strips. This results from viewing the lens at angles greater than
the critical angle for total internal reflection of a "reverse
ray." Thus, the effective width of each stripe grows as the lens is
viewed at higher viewing angles, which is observed as the lens
becoming dimmer at higher viewing angles.
[0119] In the vertical planes extending between the longitudinal
axis of the reflector assembly base member and an axis transverse
to the base member longitudinal axis, higher view angle control is
achieved through a combination of the high angle control proffered
by the linearly extending array of prismatic elements of the lens,
as discussed immediately above, and the lens assembly being
recessed within the reflector assembly. In the vertical plane
substantially parallel to the base longitudinal axis of the
reflector assembly, the optical elements of the lens assembly,
i.e., the array of prismatic elements, exert primary glare control
of the higher viewing angles. In the vertical plane substantially
transverse to the base longitudinal axis of the reflector assembly,
the recessed position of the lens assembly within the reflector
assembly exerts primary glare control of the higher viewing
angles.
[0120] In one aspect, if the prismatic elements 122 are regularly
spaced apart, the striping effect would also be regularly spaced.
In another aspect, the prismatic elements 122 of the present
invention can be sized and shaped to ensure some total internal
reflection at all viewing angles so that the "striping" is
perceptible at all viewing angles.
[0121] In use, normal movement of a viewer in the room does not
change the viewer's vertical angle of view relative to the light
fixture very rapidly and at far distances the stripes become less
distinct. Therefore, the change is stripe width is not perceived as
a dynamic motion but rather as a subtle changing of the overall
lens brightness (i.e., brighter at low vertical angles and dimmer
when viewed at high vertical angles).
[0122] The rounded or curved surface portions of each prismatic
element 122 provide a wide spreading or diffusion of any incident
light. The high degree of diffusion helps to obscure the image of
the light source 12 as seen through the lens 110 even when the
light source is in relatively close proximity to the face of the
lens 110 that is oriented toward the light source. This becomes
increasingly apparent as the lens is viewed at higher vertical
angles in the vertical plane substantially parallel to the light
source.
[0123] In another aspect, the rounded or curved surface portions of
the prismatic elements 122 provide for a gradual change in the
perceived brightness as a result of a change in the angle of view.
In yet another aspect, in an embodiment of the invention in which
each prismatic element 122 has substantially the same shape, the
dark striping and the brighter areas of the lens 110 appear to
change uniformly and smoothly from one prismatic element 122 to the
next, adjoining prismatic element 122.
[0124] Although several embodiments of the invention have been
disclosed in the foregoing specification, it is understood by those
skilled in the art that many modifications and other embodiments of
the invention will come to mind to which the invention pertains,
having the benefit of the teaching presented in the foregoing
description and associated drawings. It is thus understood that the
invention is not limited to the specific embodiments disclosed
hereinabove, and that many modifications and other embodiments are
intended to be included within the scope of the appended claims.
Moreover, although specific terms are employed herein, as well as
in the claims which follow, they are used only in a generic and
descriptive sense, and not for the purposes of limiting the
described invention, nor the claims which follow.
* * * * *